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<head><meta charset="utf-8"><title>NewPM · t-compiler/wg-llvm · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/index.html">t-compiler/wg-llvm</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html">NewPM</a></h3>

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<a name="233230190"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233230190" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Nikita Popov <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233230190">(Apr 05 2021 at 21:07)</a>:</h4>
<p>I've put up <a href="https://github.com/rust-lang/rust/pull/83894">https://github.com/rust-lang/rust/pull/83894</a> to enable the new pass manager by default.</p>



<a name="233234326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233234326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> cuviper <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233234326">(Apr 05 2021 at 21:31)</a>:</h4>
<p>that's impressive, but why do bootstrap times look so different?</p>



<a name="233235366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233235366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233235366">(Apr 05 2021 at 21:41)</a>:</h4>
<p>possibly different cgu counts or something, the perf server iirc constrains to cgu=1, but I might remember wrong</p>



<a name="233235399"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233235399" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233235399">(Apr 05 2021 at 21:41)</a>:</h4>
<p>no, just -j1</p>



<a name="233237493"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233237493" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> matthiaskrgr <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233237493">(Apr 05 2021 at 22:02)</a>:</h4>
<p>looks like memory usage increases quite a bit (10-5%)</p>



<a name="233237544"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233237544" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> matthiaskrgr <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233237544">(Apr 05 2021 at 22:02)</a>:</h4>
<p>are opt perf benchmarks using lto?</p>



<a name="233237866"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233237866" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233237866">(Apr 05 2021 at 22:05)</a>:</h4>
<p>default settings -- I think yes? iirc we default to thinlto</p>



<a name="233266376"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233266376" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233266376">(Apr 06 2021 at 04:50)</a>:</h4>
<p>Could the difference be caused by a different runtime performance?</p>



<a name="233266417"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233266417" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233266417">(Apr 06 2021 at 04:51)</a>:</h4>
<p>E.g. were not in lining something that was important before and that's causing compiler to run for longer.</p>



<a name="233266429"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233266429" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233266429">(Apr 06 2021 at 04:51)</a>:</h4>
<p>(hm but then it would be reflected in regular benchmarks too...)</p>



<a name="233301521"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187780-t-compiler/wg-llvm/topic/NewPM/near/233301521" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/187780-t-compiler/wg-llvm/topic/NewPM.html#233301521">(Apr 06 2021 at 11:16)</a>:</h4>
<p>Yeah, seems odd. I think we may bump the lto inline threshold in rustbuild though?</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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